1. Industrial Field of the Invention
The present invention relates to an eyeglasses frame tracing device which is convenient for use in an eyeglasses grinding machine.
2. Description of the Related Art
In recent years, a lens grinder which automatically grinds an edge of an eyeglasses lens has been popularized rapidly. At the same time, various kinds of eyeglasses frame tracing devices for previously measuring data related to a variable radius of a lens frame have been developed. However, any of these eyeglasses frame tracing devices measures the variable radius data of the lens frame by two dimensions so that it cannot determine correctly a curved outline of the lens frame having three dimensions.
Under such circumstance, various kinds of eyeglasses frame tracing devices for correctly determining a curved outline of a lens frame having three dimensions have recently been proposed. Two detectors are required for positional detection in such three-dimension eyeglasses frame tracing device, in order to detect an amount of displacement along the lens frame in a direction of a variable radius and an amount of displacement of the lens frame in a direction perpendicular to the variable radius.